Coordination Oligomers Research Articles

Design and solvothermal synthesis of luminescent copper(i)-pyrazolate coordination oligomer and polymer frameworks

Two luminescent coordination compounds, [Cu(Pz)]3 (1) and [Cu2(Bpz)]n (2), were isolated from solvothermal reactions of Cu(NO3)2 with 3,5-dimethylpyrazole (HPz) and 3,3',5,5'-tetra-methyl-4,4'-bipyrazole (H2Bpz) respectively in the presence of NH3, of which 1 was revealed to be a planar trimer and 2 a three-dimensional framework, presenting a rare 3-connected binodal (6(2).10)(6.10(2)) topology and eight-fold interpenetration.

Lanthanide−Potassium Wheels

Mixed potassium-lanthanide wheel-shaped-structured, hexanuclear coordination oligomers of composition [(eta5-C5H5)Ln(NPh2)2{N(PPh2)2}2K2(THF)4]2 (Ln = Er (1a), Yb (1b)) and an octanuclear coordination polymer of composition [(eta5-C5H5)Sm(NPh2)2{N(PPh2)2}K]infinity (2) were synthesized. All presented compounds can be obtained in moderate yields in a one-pot procedure, in which the potassium salts KNPh2 and [K(THF)(n)N(PPh2)2] as well as NaC5H5 are reacted with anhydrous samarium, erbium, and ytterbium trichloride in THF.

Dipyrrin–Porphyrin Hybrids: Potential π-Conjugated Platform to Fabricate Coordination Oligomers

Abstract Bis-dipyrrin-appended porphyrin derivatives, potential building blocks for supramolecular coordination architectures, were synthesized and exhibited complexation at the two dipyrrin sites with BF2 and Rh(CO)2.

Highly Stable Olefin—Cu(I) Coordination Oligomers and Polymers

AbstractFor Abstract see ChemInform Abstract in Full Text.

Structural and Photophysical Properties of Coordination Networks Combining [Ru(bipy)(CN)4]2- Anions and Lanthanide(III) Cations: Rates of Photoinduced Ru-to-Lanthanide Energy Transfer and Sensitized Near-Infrared Luminescence

Co-crystallization of K2[Ru(bipy)(CN)4] with lanthanide(III) salts (Ln = Pr, Nd, Gd, Er, Yb) from aqueous solution affords coordination oligomers and networks in which the [Ru(bipy)(CN)4]2- unit is connected to the lanthanide cation via Ru-CN-Ln bridges. The complexes fall into two structural types: [{Ru(bipy)(CN)4}2{Ln(H2O)m}{K(H2O)n}] x xH2O (Ln = Pr, Er, Yb; m = 7, 6, 6, respectively), in which two [Ru(bipy)(CN)4]2- units are connected to a single lanthanide ion by single cyanide bridges to give discrete trinuclear fragments, and [{Ru(bipy)(CN)4}3{Ln(H2O)4}2] x xH2O (Ln = Nd, Gd), which contain two-dimensional sheets of interconnected, cyanide-bridged Ru2Ln2 squares. In the Ru-Gd system, the [Ru(bipy)(CN)4]2- unit shows the characteristic intense (3)metal-to-ligand charge transfer luminescence at 580 nm with tau = 550 ns; with the other lanthanides, the intensity and lifetime of this luminescence are diminished because of a Ru --> Ln photoinduced energy transfer to low-lying emissive states of the lanthanide ions, resulting in sensitized near-infrared luminescence in every case. From the degree of quenching of the Ru-based emission, Ru --> Ln energy-transfer rates can be estimated, which are in the order Yb (k(EnT) approximately 3 x 10(6) sec(-1), the slowest energy transfer) < Er < Pr < Nd (k(EnT) approximately 2 x 10(8) sec(-1), the fastest energy transfer). This order may be rationalized on the basis of the availability of excited f-f levels on the lanthanide ions at energies that overlap with the Ru-based emission spectrum. In every case, the lifetime of the lanthanide-based luminescence is short (tens/hundreds of nanoseconds, instead of the more usual microseconds), even when the water ligands on the lanthanide ions are replaced by D2O to eliminate the quenching effects of OH oscillators; we tentatively ascribe this quenching effect to the cyanide ligands.

From a Monomer to a Protein‐Sized, Doughnut‐Shaped Coordination Oligomer—The Influence of Side Chains of C3‐Symmetric Ligands in Supramolecular Chemistry

Herein we describe the importance of side chains in C3-symmetric ligands in supramolecular chemistry. The reaction of the new ligand tris(5-bromo-2-methoxybenzylidene)triaminoguanidinium chloride [H3Me3Br3L]Cl (1) with ZnCl2 results in the formation of the monomeric complex (Et3NH)2[(ZnCl2)3Me3Br3L] (2), in which the ligand remains in a conformation less favourable for the coordination of metal centres. The use of the related tris(5-bromo-2-hydroxybenzylidene)triaminoguanidinium chloride, [H6Br3L]Cl, under similar conditions, results in the formation of two different dimeric compounds (NH4)[{[Zn(NH3)]3Br3L}2{mu-(OH)}3]1/4MeOH (3) and [Zn{Zn2(OH2)3(NH3)Br3L}2] (4), depending on the solvent mixture used. The comparable reaction of the ligand tris(5-bromo-2-hydroxy-3-methoxybenzylidene)triaminoguanidinium chloride [H6(OMe)3Br3L]Cl (5), leads to the formation of a doughnut-shaped, protein-sized coordination oligomer (Et3NH)18[{Zn[Zn2Cl{(OMe)3Br3L}]2}6(mu-Cl)6(OH2)6]x CH3CN (6), which comprises six dimeric [Zn5{(OMe)3Br3L}2] units. Whereas 3 and 4 decompose in DMSO solution, 6 is surprisingly stable in the same solvent.

Highly stable olefin–Cu(i) coordination oligomers and polymers

Highly stable Cu(I)-olefin coordination oligomers and polymers have been successfully prepared and applied to construct metal-organic frameworks (MOFs) with interesting physical and chemical functions in recent years. In this review, we present the olefin-Cu(I) coordination oligomers and polymers and their novel physical properties. From structure to functions, particular emphasis is placed on the coordination and organometallic chemistry of olefin-Cu(I) coordination oligomers and polymers, their structures and potential applications as solids possessing unusual physical functional properties such as electrochemical, chiral separation, fluorescent sensing and ferroelectricity.

New bis-, tris- and tetrakis(pyrazolyl)borate ligands with 3-pyridyl and 4-pyridyl substituents: synthesis and coordination chemistry

The new ligands dihydrobis[3-(4-pyridyl)pyrazol-1-yl]borate [Bp(4py)]-, hydrotris[3-(4-pyridyl)pyrazol-1-yl]borate [Tp(4py)]-, tetrakis[3-(4-pyridyl)pyrazol-1-yl]borate [Tkp(4py)]-, dihydrobis[3-(3-pyridyl)pyrazol-1-yl]borate [Bp(3py)]-, hydrotris[3-(3-pyridyl)pyrazol-1-yl]borate [Tp(3py)]- and tetrakis[3-(3-pyridyl)pyrazol-1-yl]borate [Tkp(4py)]- are derivatives of the well known bis-, tris- and tetrakis-(pyrazolyl)borate cores, bearing 4-pyridyl or 3-pyridyl substituents attached to the pyrazolyl C3 positions. These pyridyl groups cannot chelate to the metal ions in the poly(pyrazolyl) cavity but are externally directed. Structural studies on a range of metal complexes show how, in many cases, coordination of these pendant pyridyl groups to the M(pyrazolyl)n core of an adjacent metal complex fragment results in formation of coordination oligomers or polymeric networks. [Tl(Bp(3py))], [Tl(Bp(4py))] and [Tl(Tp(4py))] form one-dimensional polymeric chains via coordination of one of their pendant pyridyl units to the Tl(I) centre of an adjacent complex fragment; in contrast, in [Tl(Tp(3py))] coordination of all three pendant pyridyl units to separate Tl(I) neighbours results in formation of a two-dimensional polymeric sheet. In [Tl(Tkp(3py))] and [Tl(Tkp(4py))] the Tl(I) is coordinated by two or three of the four pyrazolyl arms, respectively; bridging interactions of pendant 4-pyridyl groups with adjacent Tl(I) centres result in a two-dimensional sheet forming in each case. In Ag(Tkp(4py)) each Ag(I) ion is coordinated by two pyrazolyl rings, and two bridging pyridyl ligands from other complex units, resulting in a one-dimensional chain consisting of pairs of cross-linked zigzag chains. In contrast to these polymeric coordination networks, the structures of [Cu(Tp(4py))] and [(Tp(3py))Cd(CH3CO2)] are dimers, with a pendant pyridyl residue from the first metal centre attaching to a vacant coordination site on the second, and vice versa; these dimers are stabilised by pi-stacking interactions between sections of the two ligands. [Ni(Tp(3py))2] is monomeric, with an octahedral coordination geometry arising from two tris(pyrazolyl)borate chelates; the array of pendant 3-pyridyl groups is involved only in intramolecular hydrogen-bonding. [(Tp(4py))Re(CO)3] is also monomeric, with a facial arrangement of three pyrazolyl ligands and three carbonyls, with the pendant 4-pyridyl groups not further coordinated. [(Tp(2py))Re(CO)3], based on the related ligand hydrotris[3-(2-pyridyl)pyrazol-1-yl]borate, has a similar fac-(CO)3(pyrazolyl)3 coordination geometry.

Ortho-chalcogenostannates as ligands: syntheses, crystal structures, electronic properties, and magnetism of novel compounds containing ternary anionic substructures [M4(mu4-Se)(SnSe4)4]10- (M=Mn, Zn, Cd, Hg), 3(infinity)[[Hg4(mu4-Se)(SnSe4)3]6-], or 1(infinity)[[HgSnSe4]2-

By reaction of K4[SnSe4].1.5 MeOH with CdCl2 or Hg(OAc)2 in water/methanol it was possible to prepare single crystals of four novel compounds that contain ternary anionic coordination oligomers and polymers: [K10(H2O)16(MeOH)(0.5)][M4(mu4-Se)(SnSe4)4] (4: M=Cd, 5: M=Hg), [K6(H2O)3][Hg4(mu4-Se)(SnSe4)3].MeOH (6), and K2[HgSnSe4] (7), which were structurally characterized by single-crystal X-ray diffraction. The optical absorption properties of the isostructural compounds 4 and 5, as well as those of the recently reported Zn (2) and Mn (3) analogues, were studied by UV-visible spectroscopy. These investigations showed the quaternary phases to have relatively small optical gaps for their molecular size (2.2-2.6 eV), which are similar to the excitation energies that were observed for mesostructured solids of the respective combination of elements. According to DFT investigations on the ternary anions, an experimentally observed difference between the absorption behavior of the d10 compounds 2, 4, and 5 and the open-shell d(5) compound 3 is in line with different characters of the frontier orbitals in the two cases. Both the calculations and a magnetic measurement on 3 demonstrated antiferromagnetic coupling between the mu(4)-Se-bridged Mn centers.

Structure and dynamics of copper complexes with 2,2′:6′,2″-terpyridines in glassy matrices

Continuous-wave and pulse electron paramagnetic resonance (EPR) as well as electron-nuclear double resonance (ENDOR) techniques are applied for determination of the electronic and geometric structure of copper(II) complexes with terpyridine and related ligands that are relevant in the context of supramolecular chemistry. The results are analysed in conjunction with density functional theory computations and are compared to the crystal structure of the bis(terpyridyl) copper(II) complex in the limit of static Jahn–Teller distortion (R. Allmann, W. Henke and D. Reinen, Inorg. Chem. 1978, 17, 378, ). The static structure in disordered environments is subject to some strain in both the g-values and copper–ligand distances, but otherwise is rather similar to the structure in crystals. The formation of coordination oligomers is indicated by broadening of the lineshape and a decrease in the transverse relaxation time at low fields which are both related to exchange coupling between copper centres. At high fields of approximately 3 T and a temperature of 15 K, the transverse relaxation rate is governed by modulation of the g-values induced by small-amplitude libration along the Jahn–Teller active mode. A study of the dynamics in a temperature range from below the glass transition temperature to above the melting point of ethanol by CW EPR reveals that the complex is a sensitive probe for matrix dynamics, which detects dynamic heterogeneities and the transition from the structural glass to the crystalline phase. Jahn–Teller dynamics is completely unfrozen only on melting of the matrix.

Synthesis, structure, and reactivity of siloxides and germyloxides of iron(II) and cobalt(II)

Iron and cobalt siloxides and germyloxides [(Me3Si)3SiO]2M (M = Fe (1), Co (2)), (Me5Si2O)2Fe (3), (Pri3SiO)2M (M = Fe (4), Co (5)), (Pri3GeO)2Fe (6), (Ph3SiO)2Fe (7), (Me3SiO)2Fe (8), (Pri3GeO)2Fe(bpy) (9), and [(Me3Si)2NFe(μ-OSi2Me5)2]2Fe·C6H6 (10) were synthesized by the reactions of metal silylamides [(Me3Si)2N]2M (M = Fe, Co) with the corresponding silanols or triisopropylgermanol. The reaction of pentamethyldisilanol with iron(ii) silylamide affords either polymeric complex 3 or coordination oligomer 10, depending on the ratio of the reactants. The structures of complexes 9 and 10 were established by X-ray diffraction analysis. The interaction of the prepared compounds with carbon oxides was studied. Low-coordination cobalt siloxide is the only among all prepared compounds that absorbs CO (2 mol) at room temperature and under 1 atm to form an unstable cluster. Compounds 1, 2, and 4—8 react with CO2 to form carbonate complexes, and their reactivity decreases with a decrease in the electron-donating ability of the substituents at the central atom: (Me3Si)3SiO > Pri3GeO ≈ Pri3SiO > Me3SiO ≫ Ph3SiO.

A remarkable 14-nuclear Re(8)(V) Ag(I)(6) coordination oligomer derived from a 2D (Re(2)(V) Ag(I)(2))n coordination polymer with D-penicillaminate.

ReV polymer/oligomer switching: The aggregation of ReV octahedra, [ReO(d-pen-N,O)(d-pen-N,O,S)]− (d-H2pen=d-penicillamine), assisted by AgI ions, leads to the formation of a 2D (ReAg)n coordination polymer 1, which is converted into a ReAg coordination oligomer 2 (see picture; Ag green, S yellow, Re purple, O red, N blue). While 1 results from the self-assembly of ReAg units through AgO coordination bonding, the self-assembly of ReAg molecules in 2 is through COOH⋅⋅⋅OOC hydrogen bonding.

Supramolecular assembly of metalloporphyrins in crystals by axial coordination through amine ligands

Axial coordination to metalloporphyrins is an important tool in the supramolecular chemistry of these entities. Metalated 5,10,15,20-tetraphenylporphyrins can be axially linked to each other with the aid of amine and diamine ligands. Seven new crystalline materials consisting of such heterogeneous coordination oligomers and polymers of Zn(II)– or Mn(III)–tetraphenylporphyrins have been prepared and characterized by X-ray crystallography. Ligands of varying length have been used as bridging auxiliaries between the metal centers of the porphyrin species, effecting heterogeneous porphyrin-ligand oligomeric as well as polymeric assemblies. These correspond, respectively, to “wheel-and-axle” and “shish-kebab” type shapes of the supramolecular scaffolds. In addition, a uniquely structured homogeneous coordination polymer of a Zn(II)–tetrapyridylporphyrin derivative, is also reported.

A New Class of Easily Obtained Carbonate-Related μ3 -Ligands and a Protein-Sized Doughnut-Shaped Coordination Oligomer.

Guanidine-based ligands can be prepared by a very simple synthesis. These ligands are amenable, in principle, to wide variation and in the anionic form are able to bind three metal centers simultaneously at chelating sites in close proximity (see picture). An oligomer which contains 24 Cd centers, 12 of the ligands shown, and 6 ligands isomeric to them and which forms a doughnutlike ring with a diameter of >30 Å has been characterized.

Redox Reactivity as the Controlling Element in Coordination Polymer Stereochemistry: Redox-Switched Growth Mechanism in the [Fe(II)-CN-Pt(IV)](n)() System.

Coordination oligomers and polymers composed of [(CN)(5)Fe(II)-CN-Pt(IV)(NH(3))(4)] units have been synthesized. The oligomer growth mechanism is based on the oxidation state of the iron centers which can be specified either chemically or electrochemically to allow control over oligomer structure. Cyclic voltammetry is found to be a sensitive probe of oligomer and polymer structure. (13)C NMR is also shown to be a useful technique for characterizing the different geometric isomers. Thin films composed of [-(NC)(5)Fe(II)-CN-Pt(IV)(NH(3))(4)-](n)() were electropolymerized onto transparent indium tin oxide (ITO) electrode surfaces and characterized with regard to polymer morphology.

Metal‐directed assembly of coordination oligomers

AbstractBridging ligands containing two spatially separated 2,2′:6′,2′‐terpyridinyl metal‐binding domains have been prepared and used for the controlled assembly of coordination oligomers incorporating ruthenium(II) and other metal ions. Two such bridging ligands have been structurally characterised. The systematic synthesis of a range of homo‐ and heterometallic polynuclear complexes incorporating these bridging ligands and a variety of terminator 2,2′:6′,2′‐ terpyridines is described.

A principle for the assembly of novel mononuclear building blocks for supramolecular chemistry

Abstract The controlled assembly of supramolecular coordination oligomers may be achieved by the use of multinucleating ligands which contain two or more metal-binding domains. Examples of such ligands commonly consist of discrete metal-binding sites linked by appropriate spacers. We now show that a consideration of the donor properties of a ligand and the acceptor properties of a metal ion may be used to induce multinucleating behaviour in oligopyridine ligands which conventionally chelate to single metal centres. Such species are key building blocks for the assembly of a variety of supramolecular species in which the non-coordinated donor atoms may later interact with other metal centres. The crystal structure of the complex [Ru(bpy-N,N′)2(tpy-N,N′)][PF6]2 ( P 1, a = 8.367(2), b = 11.821(4), c = 19.398(5)A, α = 93.83(2), β = 92.25(2), γ = 89.62(2)°, Z = 2, d c = 1.63 g cm−3, 5084 unique observed reflections with I < 1.5σ(I), R = 0.0745) which contains a bidentate tpy ligand is presented.

A new organic conducting material derived from 1,4-diaminoanthraquinone

Conducting organic materials have drawn considerable attention due to the exciting possibilities of creating metallike conductivity and superconductivity and the potential applications of their interesting electrical, optical, and magnetic properties. The discovery of metallic conductivity in molecular organic systems was a breakthrough that aroused the interest of chemists, physicists, and theorists. High conductivities have also been achieved in oxidized/reduced polymers such as phthalocyanines, polyacetylenes, poly(p-phenylenes) polypyrrole, and polyani1ine. Several planar coordination oligomers possessing intrinsic electrical conductivity have been reported in the literature. Coordination complexes of 1,4di aminoanthraquinone with different metal atoms have been studied recently. Here, we report the synthesis, characterization, and low-temperature conducting properties of a novel conducting material formed by oxidizing 1,4-diaminoanthraquinon(1,4-DAAQ)with cerium(IV). The complex formed is stable at ambient conditions with very interesting conducting properties.

Multinucleating 2,2′ : 6′,2″-terpyridine ligands as building blocks for the assembly of co-ordination polymers and oligomers

The co-ordination properties of the tridentate ligand 2,2′ : 6′,2″-terpyridine (terpy) make it an ideal structural unit from which to assemble co-ordination oligomers and polymers with a linear connectivity about the metal centre. The dinucleating ‘back-to-back’ 2,2′ : 6′2″-terpyridine ligands 6′,6″-bis(2-pyridyl)-2,2′ : 4′,4″ : 2″,2‴-quaterpyridine L1 and 1,4-bis(2,2′ : 6′,2″-terpyridin-4′-yl)benzene L2 give rise to a linear connectivity at the ligand, whereas 1,3,5-tris(2,2′ : 6′,2″-terpyridin-4′-yl)benzene L3 is a trinucleating species which can give rise to arrays with a connectivity of three at the ligand. The co-ordination oligomers [(X-terpy)RuLRu(X-terpy)]4+(L = L1 or L2) and [{(X-terpy)Ru}3L3]6+(X-terpy = 4′-substituted 2,2′ : 6′,2″-terpyridine) have been prepared and characterised for a variety of electron-donating and -withdrawing substituent groups X.

A new ligand for the self assembly of starburst coordination oligomers and polymers

Download options Please wait... Article information DOI https://doi.org/10.1039/C39920000617 Article type Paper Download Citation J. Chem. Soc., Chem. Commun., 1992, 617-619 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions A new ligand for the self assembly of starburst coordination oligomers and polymers E. C. Constable and A. M. W. C. Thompson, J. Chem. Soc., Chem. Commun., 1992, 617 DOI: 10.1039/C39920000617 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Edwin C. Constable Alexander M. W. Cargill Thompson